Population growth, natural and other events have stimulated the farming industry to seek technological advances in raising crops. Studies indicate by the year 2050 there may be 9 billion people inhabiting the earth. Given the limited area of land in relation to population growth, agricultural productivity is limited. As a result, solutions to assist with limited crop productivity are given consideration. One such area of interest is the field of vertical farming. In vertical farming, buildings may be used to grow crops that may not be otherwise grown on land.
Growing crops within buildings and vertical farms require the usage of powered lighting to provide essential light for plants growing within buildings. These “plant” lights or “grow” lights may be electrically powered lights that emit a spectrum of lights used for photosynthesis. Examples of various “plant” light sources include metal halide light, fluorescent light, high-pressure sodium light, incandescent light and LEDs (light emitting diode).
The vast majority of these lights were made to maximize the lumen content or tailored toward the human eye response, the photopic response. Plants generally do not respond optimally to the human photopic vision curve, which emphasizes green light. Photosynthetic chlorophylls, and other accessory pigments, respond better to blue and red light. Green light is mainly reflected from plants and so plants tend to exhibit various ranges of the color green.
LED lights in particular have peaked interest in growing indoor crops as LEDs provide for bright, cost-effective and long lasting light that can emit various wavelengths of light that encourage the photosynthetic process in plants. In addition to vertical farms, LED lighting suitable for a wide range of plant-growing applications, e.g. algal cultures, tissue cultures, germination and growth chambers, green houses, aquatic plants, supplemental lighting in such facilities and the like. Given the stimulating response to red and blue light to plant growth, current LED products for horticulture lighting focus primarily on the blue and red spectrum.